This proposal requests a new training grant in physical biosciences, to replace the expiring non-renewable NSF IGERT grant in Physical Biosciences. The program will be administered by the interdisciplinary Graduate Group in Biophysics. Its 35 faculty mentors are drawn from the departments of Bioengineering, Chemical Engineering, Chemistry, Integrative Biology, Molecular and Cell Biology, Physics, Psychology, Public Health, and Vision Science. The 12 trainees may matriculate in any participating department, but must have a research focus in one of five research areas in biomedical imaging and bioengineering in which this campus excels, namely: 1) single molecule / single cell mechanics and dynamics, 2) molecular microscopy and optical-electrical probes, 3) brain imaging and systems neuroscience, 4) computational biology, and 5) biomechanics and animal locomotion. The program attracts physical scientists to the quantitative study of biological problems, and trains them flexibly and broadly for emerging disciplines, making use of the extraordinary research facilities of UCB and the adjacent Lawrence Berkeley National Laboratory, with whom many of the faculty are associated. No other training grant on campus supports these areas. The program is characterized by intensive advising, tracking, and counseling, and individualized curricula designed to provide breadth and depth appropriate to each trainee's interests and background. Initially, trainees take graduate level survey and comprehensive courses, followed by specialized laboratory and focus courses, directed reading and oral presentation courses, and graduate seminars. They attend an annual biophysics retreat, laboratory meetings, and journal clubs, receive teaching experience, and perform original dissertation research in the final years. The expiring IGERT program has attracted outstanding students and provided core support for the first two years of study, supplemented with Graduate Student Instructor stipends, plus UCB, individual NRSA, and private foundation scholarships that support additional trainees. Minority applicants have been welcome and are succeeding in the program. This grant will allow UCB to continue in its tradition of training the best biomedical researchers who provide the scientific foundation for the improvement of modern medical practice and extending the health and well being of the American public.